Speakers in a glass elevator?

[hong-kai]

Hi,

I am working on a sound installation proposal to be staged in a glass elevator shaft and researching on the type of speakers that will best suit the acoustic properties of the elevator. The building has 4 flights and I plan to install a mono speaker (full range with good low frequency response) on each floor in the shaft. Each speaker consists of different audio source. Can anybody suggest/recommend the type speaker and possibly the hardware I should get?

Many thanks for your inputs. Hope to hear from you!

[WMcD]

Thank you for stopping by this forum and bringing an interesting, creative inquiry.

If I understand, there is to be a different audio program for each floor. Something like that is done here in Chicago at Midway Airport in the waiting areas for the elevator. My recall is that the song "Three Coins in a Fountain" is on floor three. "Fiddler on the Roof" is on the top floor. Funny.

Reading your post, I'm not clear on where the speakers are to be placed. One read is that the sound is to pass thought the glass shaft walls and into the glass cabin. That is a tough thing to do with any good sound quality. There is going to be a lot of attenuation of sound at different frequencies. But perhaps you're contemplating speakers in the cabin or the halls, as an alternative.

In any case, you should take a look at the main page for www.klipsch.com . The company makes a number of in-wall and in-ceiling speakers which can be used.

But one should ask whether these are superior. I do think so because of the use of horns for the high frequencies. These would tend to control the direction of sound away from glass walls.

The only rough analogy to what you're dealing with is listening to a Sony Tap-Tunes radio in a shower or bath enclosure, like I have.. I've found that opening the door a little bit causes a remarkable change in acoustics. It may be that in your project, the directional charictaristics of the horn helps too.

Gil

[hong-kai]

Thanks very much for your input, Gil. I was just thinking if in-wall or in-ceiling speakers can be used.

The most ideal setup is to install speakers on each floor in the shaft so when the elevator car (also made of glass) travels through the glass shaft, sounds would drift in and out of earshot. I am aware of the possibility of a lot of attenuation of sound since the the car is enclosed in the glass. If the speakers are placed in the car, this would be become a different installation piece, conceptually.

I am thinking of using at least 150-Watts speakers to connect with an amplifier - do you think it would suffice?

Thanks again!

[tenzip]

Thanks very much for your input, Gil. I was just thinking if in-wall or in-ceiling speakers can be used.

The most ideal setup is to install speakers on each floor in the shaft so when the elevator car (also made of glass) travels through the glass shaft, sounds would drift in and out of earshot. I am aware of the possibility of a lot of attenuation of sound since the the car is enclosed in the glass. If the speakers are placed in the car, this would be become a different installation piece, conceptually.

I am thinking of using at least 150-Watts speakers to connect with an amplifier - do you think it would suffice?

I think the sound quality will be horrible through the glass elevator, and leakage out of the shaft might be a concern also. (If it's heard clearly inside the glass elevator, it will be heard clearly outside the glass shaft, right?) I'd look hard for a solution that would use one speaker in the elevator, and some kind of interface with the elevator controller that would fade from one song to another as the elevator moved. The supplier of your elevator equipment may be able to help, I'd think.

Even if you have to have some custom electronics work done, the cost difference may not be that much, as you'll only need one speaker/amp/source, instead of 4 of each, and it won't have to be a big amp either.

I didn't think I'd ever see someone ask what Klipsch speakers to use for Muzak. []

[mas]

If you are only looking for a speaker to provide coverage inside the elevator, I would use a ceiling mounted speaker. This is one application where the zone aspect of the speaker would be extremely beneficial as the multiple reflections off the glass will render the intelligibility 'lacking'.

A medium/ high Q driver will work just fine.

I still am unclear as to what you want the sound to do as it passes each floor. If you want the program to change inside the elevator as it passes each floor, I can only imagine what that would sound like - rather like someone quickly spanning the dial on an analog tuner - and I wonder what benefit aside from noise masking that would avail! I know I wouldn't want to hear little snippets of out of context program material.

Many options are available, but I still need a better understanding of what form this multi-floor program material is supposed to be - and what the program material would be as well in context with the change in floors. What is the end goal? Both for those outside the elevator (if that matters) and for those inside the elevator.

[michael hurd]

What about using something like a cheap low powered wireless transmitter for each floor and a speaker inside the elevator?? That would make more sense if you could arrange it so that you can only hear one program at time, otherwise it would be a jumbled mess. Also much more intelligble.

[Coytee]

If you want the program to change inside the elevator as it passes each floor, I can only imagine what that would sound like - rather like someone quickly spanning the dial on an analog tuner - and I wonder what benefit aside from noise masking that would avail! I know I wouldn't want to hear little snippets of out of context program material.

MAS... get your glasses!!

He said "I plan to install a mono speaker (full range with good low frequency response) on each floor in the shaft. Each speaker consists of different audio source."

Meaning, each elevator shaft will have its own source... sort of like DISCO in shaft 1, Romantic in shaft 2, Chloe barking in shaft 3 and sounds of Sugarlips smacking in shaft 4!!

They'd hear the same sound all the way up/down but if they changed rides, the music/sound effects would be different.

[WMcD]

Pardon me, Hong Kai, I didn't see until now that you had addressed the power question to me.

Basically, I don't know. My guess is that given the attenuation, you are going to need many speakers and a lot of amplifier power. The actual attenuation through glass maybe 40 dB or more and that equates to a lot of acoustic power. Far more than you can create with one speaker on a given floor and a 150 watt amp on each floor.

As far as music choice, that is VERY interesting. I should leave that to real musicians or people who know music. Larry C is a suggested source. As pointed out by others, it could be like scanning a radio dial. But it does not have to be.

I'll pass along three observations. Using them would require some very good synchonzation of music program. This is a tall order.

1) At one time I could play some of Bach's Tocca and Fuge. He would start a melody pattern in the left hand and then toss it over to the right hand, with an accompanying new melody in the left. Then he moves the new left over to the right, and puts in another new left hand. All mesh beautifully.

My knowledge is not sufficent to allow me to say how often Bach did this in his compositions. However, it does show that some melody patterns do interlock or mesh well (if you use Bach's genius) and perhaps if any two of these are on adjacent floors, it could work.

BTW, King Crimson mentions "The Pattern Juggler". In my mind, that is Bach.

2) You might listen to "Love" which is the new remix of Beatles' songs. In some spots there is a seamless blend and overlap. I suppose it just shows they were written in the same key and tempo. Again, this shows some potental for simultaneous but different music cuts having a natural mix as the cab moves from one source to another.

3) Philip Glass. Much of his music sounds the same and is repetitious. But they say that about Vivaldi too. Either they have 1000 compositions or one composition with 1000 variations. Maybe Glass or Vivaldi music could be used.

Please keep us all informed on where you project leads you.

Gil

[mas]

If you want the program to change inside the elevator as it passes each floor, I can only imagine what that would sound like - rather like someone quickly spanning the dial on an analog tuner - and I wonder what benefit aside from noise masking that would avail! I know I wouldn't want to hear little snippets of out of context program material.

MAS... get your glasses!!

He said "I plan to install a mono speaker (full range with good low frequency response) on each floor in the shaft. Each speaker consists of different audio source."

Meaning, each elevator shaft will have its own source... sort of like DISCO in shaft 1, Romantic in shaft 2, Chloe barking in shaft 3 and sounds of Sugarlips smacking in shaft 4!!

They'd hear the same sound all the way up/down but if they changed rides, the music/sound effects would be different.

Silly me, as the part I read with my glasses was this: "The most ideal setup is to install speakers on each floor in the shaft

so when the elevator car (also made of glass) travels through the glass

shaft, sounds would drift in and out of earshot."

Now that this is clarified, you have a couple of options.

First, you would not want to employ the above scenario. The sound experienced within the passing elevator car would be characterized by doppler shift and your elevator would become a bad fun house ride.

Additionally, sound transmission through the glass would not be a reasonable option. This

is akin to putting a speaker in another sealed room and expecting the

drywall to act as an accurate transmission source! Transients aside,

the impedance of the glass would make for a very interesting (a polite way of saying "terrible") transmission medium.

Second, an in the ceiling speaker with a moderately high Q would be suitable for mounting in the elevator - not the shaft. This would control dispersion and optimize coverage and reduce reflections. Volume would be low to moderate at most.

Third, as far as a source, you have several options. First it would be helpful to know what powering options exist in the elevator. It is normal for them to have power capabilities, the only limit being the voltage and current capabilities.

You could employ a small locally powered amplifier. A small digital amp that can be run off 12V would be ideal and it would provide all of the power that is necessary.

As far as a source is concerned, the preferred method would be a small 12V portable CD player with a repeating CD. Material would simply be chosen by selection of th CD or by selection of the radio tuner. CD would be much easier. Also, if site specific material is required, CD would also allow for the easy production and distribution of said material.

The other less optimal choice, would be to employ a radio receiver. A radio may be problematic due to

reception issues due to the grounding of the building's frame which will tend to obscure an external

signal, or even a local signal. Also, you would want to perform a quick spectral analysis with a spectrum analyzer to identify the existing signal frequencies.

Wireless would be more problematic depending upon the wireless format chosen. If on a fixed shared frequency for the system,(all shafts), the propagation pattern is not amenable to a long narrow focused field offering sufficient gain and isolation from the adjacent transmitter at the far end of the shaft (In other words, the pattern is not sufficiently collimated to allow such well behaved propagation without adjacent shaft interference if using the same frequency). If however you chose a system with dynamic frequency assignment, you could employ this technique and assign unique channels (frequencies) to each elevator, but you would be adding layers of complexity and cost without adding significant functionality.

It would be well to check with the manufacturer of the elevator as well. Most have capabilities for importing music, PA, and other media into the elevators, whether these options have been installed or not. Knowledge of what the manufacturer anticipated and what resources are available internally to the unit could save allot of reinvention on your part.

[Coytee]

Silly me, as the part I read with my glasses was this: "The most ideal setup is to install speakers on each floor in the shaft so when the elevator car (also made of glass) travels through the glass shaft, sounds would drift in and out of earshot."

Now that this is clarified

Dang...I'm busted again!! I missed that part.

Seems my Evelyn Wood training has worn off...